ATX电源一个有趣的问题

我在powerpc p2020rdb官方开发板的手册上看到关于atx电源的一个有意思的问题：

27.1 Some ATX power supplies do not work with the RDB?

Some ATX power supplies may need a large 5-V loading to stabilize the 3.3-V output; otherwise, you may observe the 3.3 V lowered to around 2.9 V–3 V. The consequence can be a periodic reset by the on-board voltage monitoring circuit. For a workaround, you may take one of the following actions:

• Add a 5-V loading to the power supply, for example, attach a hard disk drive.

• Change to another ATX power supply that does not require a large 5-V loading.

• Use the power supply provided with the RDB package.

 

然后我自己实验了一下，一个老旧的长城ATX电源什么也不接，万用表测黄色12V输出只有10.9V。接上一个sata硬盘再测，黄色12V输出能达到11.9。

在其他板子上也遇到ATX电源电压不稳的情况，那时确实没有接硬盘。没准真的有影响。